docs: def get_tom(self, node):
          """
          Convert the given node into a Temporal Occurrence Model object.
  
          :param node: a node of kind poissonTOM or brownianTOM
          :returns: a :class:`openquake.hazardlib.mfd.EvenlyDiscretizedMFD.` or
                    :class:`openquake.hazardlib.mfd.TruncatedGRMFD` instance
          """
          if 'tom' in node.attrib:
              tom_cls = tom.registry[node['tom']]
          else:
              tom_cls = tom.registry['PoissonTOM']
          return tom_cls(time_span=self.investigation_time,
                         occurrence_rate=node.get('occurrence_rate'))